Neurostimulation for Cognitive Enhancement in Alzheimer's Disease

Inclusion Criteria: 1. Community-dwelling male or female of age 60 and older 2. AD diagnosed by neurologists or geriatricians at our dementia and geriatric clinical sites. Clinicians will review the medical records of all potential cases to ensure the patients meet established clinical criteria for AD, and also examine individuals as needed to further establish the diagnosis. Mild-to moderate stage AD as determined by study clinicians using the Clinical Dementia Rating Scale (CDR). The CDR is a 5-point scale used to characterize six domains of cognitive and functional performance applicable to AD: Memory, Orientation, Judgment \& Problem Solving, Community Affairs, Home \& Hobbies, and Personal Care. The necessary information to make each rating is obtained through a semi-structured interview of the patient and a reliable informant (e.g., family member). A CDR score of 0.5 or 1 is rated as mild severity and a score of 2 is rated as moderate severity. The investigators selected mild to moderate AD patients as our target population as they are the most prevalent AD severity group referred to our clinics, increasing generalizability. This mild to moderate AD group is also most likely to be cared for in the community and at home, in contrast to more advanced or severe AD stages, which are more prevalent in institutional settings (and will be the focus of our future studies) 3. If on dementia medication regimen, the regimen is stable for at least 4 weeks prior to enrollment. The investigators will not restrict clinicians from starting, adjusting or stopping dementia medications over the intervention period in keeping with the pragmatic nature of our trial, but will account for medications in both groups in our analysis 4. Able to speak and understand English or Spanish at a level sufficient undergo the study procedures and testing protocols 5. Willing to complete an MRI (exclusions relevant to neuroimaging are described below) 6. Able to provide Informed Consent (or able to provide assent with a legal surrogate providing informed consent.) Exclusion Criteria: 1. Unstable medical or major psychiatric illnesses or unstable treatments for medical or major psychiatric illnesses. Any medical or psychiatric diagnosis is permitted as long as it has been clinically stable for at least 3 months, reflected in part by stability of treatments for at least 3 months, and is expected on the basis of clinical judgment to be in a stable phase that will likely extend for 6 months 2. History of head trauma, seizures, brain surgery, stroke or cancer affecting head, metal implants in the head or neck, compromised integrity or sensitivity of the skin at or near locations where electrodes will be placed (e.g., eczema, severe rashes, blisters, open wounds, burn including sunburns, cuts or irritation) 3. Currently participating in another intervention study or using neurostimulation device 4. Exclusions specific to neuroimaging procedure: the presence of any surgically implanted metallic devices, such as aneurysm clips or pacemakers that would be a safety contraindication for MRI. Subjects with large amounts of dental or surgical hardware in the head and neck will be excluded because magnetic susceptibility effects will lead to severe image artifacts in these subjects' images. Due to the confined space of the MRI magnet, subjects with a known history of claustrophobia will also be excluded as will subjects with weight \>350lbs or waist circumference \>55 inches 5. Must not be currently receiving or have received (or completed) within the past 3 months any monoclonal antibody treatment for Alzheimer's